The present invention relates to communication systems. More particularly, the present invention relates to methods and modules for constructing a frame structure in a communication system.
Orthogonal Frequency Division Multiple Access (OFDMA) is a multiple access scheme for transmitting data in different subcarriers in a channel, wherein the data may come from different users and may be transmitted in disjoint subsets of sub-channels in a transmission bandwidth. The orthogonality property among the subcarriers may allow simultaneous transmission of data from different users without interference from one other. The multiple access scheme of the OFDMA may generally be applied in various communication systems, such as those defined in IEEE standard 802.16e (“legacy system” hereafter) and IEEE standard 802.16m (“new system” hereafter). The new system defined in the IEEE standard 802.16m may be required to provide enhanced spectrum efficiency, higher speed tolerance and full backward compatibility with the legacy system defined in the IEEE standard 802.16e.
Since a communication system, either legacy or new, may have an individual frame structure for data transmission, and the legacy and new systems may operate on the same radio frequency (RF) carrier in the same channel bandwidth, it may be desirable to have a new frame structure for the legacy and new systems to coexist in a communication network while enhancing spectrum efficiency and speed tolerance.